An instructor and colleague in Oklahoma makes this important point about zeroing serious rifles:
“Many of our rifle students do not have access to private property, nor ranges that afford them the opportunity to sight-in rifles at whatever distance they might choose. On the contrary, most of us are limited to public shooting facilities, indeed mostly to pistol ranges, where targets can be set only at pre-established distances. Nearly every such outdoor public range has a targets pre-set at fifty yards, which comes out to forty-six meters.
“When thus set as the initial intersection, the second intersection for most ARs (223) will then occur at 210 meters. Bullets will subsequently drop seven centimeters below the line of sight at 250m. So, MPBR then becomes 250m. In addition, most AKs (7.62x39) sighted-in at the same forty-six meter zero will establish a second intersection at 170m. MPBR then becomes 190m. So, using this ‘46/210 Standard,’ instead of the 40/240 Standard that you advocate, allows our students to confirm zero easily, and often, on nearly any pistol range, without having to move targets around. The Standard is easily assimilated by the majority of rifles, ARs, AKs, et al, and allows the student to repeat the process on nearly any range that may be available to them, after they leave our Class.”
Comment: This is a good point!
I advise students to physically confirm rifle zero at every opportunity. I’d much rather have a recently-zeroed rifle than one that has not had zero confirmed in months, particularly when the rifle in question is transported often.
Rifles chambered for .223 are capable of being zeroed at any range, and one can make a reasonable argument for a number of different strategies, from 25/300 to 100/100.
There is scant difference between a 40/240 zero and a 46/210 one, and, when all you have access to is a 46m range, go for it!